"Displaced Threshold"?
Paxing All Over The World
Thread Starter
"Displaced Threshold"?
Am I right in understanding that this means: The threshold of the runway is separated from the tarmac itself by, for example, a perimeter road or some such? So that, on approach, there is not a 'smooth' and continuous line of sight from the threshold, to the Touch Down Zone (TDZ) and on to the rest of the black stuff?
If so, what compensations must the PF make - either physically or mentally?
If so, what compensations must the PF make - either physically or mentally?
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Other way around .. the threshold for landing is located some distance in from the end of the runway .. usually to provide for an obstacle clear approach surface to that threshold.
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Usually marked by arrows leading from the start of the black stuff to a painted threshold marking. You may not land before the threshold markings (reason above) but you may often use the area as a starter extension to begin a takeoff run.
Ohcirrej
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Not the best picture in the world (and it is a US runway 
) but.........
http://www.faa.gov/ATpubs/AIM/Chap2/F0203006.gif
) but.........http://www.faa.gov/ATpubs/AIM/Chap2/F0203006.gif
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Paxing All Over The World
Thread Starter
Ah, yes that is very clear thanks folks. In the Farnborough example, is that to reduce noise? With the sharper descent?
It would seem to me that the displaced threshold must be rather confusing? Having all of that runway there that you must not touch?
It would seem to me that the displaced threshold must be rather confusing? Having all of that runway there that you must not touch?
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There are several reasons for a displaced threshold:
1) Noise abatement in the approach sector, that means sometimes combined with steeper glidepath.
2) Temporary construction work in the approach sector.
3) Separating the approach profiles on parallel runways which are to close together, that means less separation possible and therefore more movements(landings) per hour.(Frankfurt)
4) Expected wake turbulance problems on parallel runways.
5) Runways with approach sectors over land/sea or other geological abnormalities, where up-or downdrifts are common.(Lisbon)
Confusing? Hmmm just daily bread.
Regards
1) Noise abatement in the approach sector, that means sometimes combined with steeper glidepath.
2) Temporary construction work in the approach sector.
3) Separating the approach profiles on parallel runways which are to close together, that means less separation possible and therefore more movements(landings) per hour.(Frankfurt)
4) Expected wake turbulance problems on parallel runways.
5) Runways with approach sectors over land/sea or other geological abnormalities, where up-or downdrifts are common.(Lisbon)
Confusing? Hmmm just daily bread.
Regards
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PAXboy never fear;
even if a runway has a displaced threshold, it does not stop a aircraft using the area before the threshold for take-off.
This can translate into a higher take-off weight for departing aircraft.
even if a runway has a displaced threshold, it does not stop a aircraft using the area before the threshold for take-off.
This can translate into a higher take-off weight for departing aircraft.
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Paxboy,
The displaced threshold is indeed for noise abatement for the locals at Farnborough. In fact it limits the aircraft that are allowed in and out to 737 / A320 type size.......And before anyone asks, I was told on a recent visit that apparently they get an exemption for the Farnborough Airshow and can use the full length available. I cant see clearly on the photo linked, but do I remember correctly that the old approach lights/PAPI s etc are still there for use during the show?
Regards, SD..
The displaced threshold is indeed for noise abatement for the locals at Farnborough. In fact it limits the aircraft that are allowed in and out to 737 / A320 type size.......And before anyone asks, I was told on a recent visit that apparently they get an exemption for the Farnborough Airshow and can use the full length available. I cant see clearly on the photo linked, but do I remember correctly that the old approach lights/PAPI s etc are still there for use during the show?
Regards, SD..
